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Finding the Fourth Proportional to 639, 881.46 and 390.44

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Solution

The fourth proportional to 639, 881.46 and 390.44 is: 538.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    639 : 881.46 = 390.44 : x
  2. Step 2: Convert to fraction form
    639/881.46 = 390.44/x
  3. Step 3: Cross multiply
    639x = 881.46 × 390.44
  4. Step 4: Simplify right side
    639x = 344,157.24
  5. Step 5: Solve for x
    x = 344,157.24/639
  6. Step 6: Final answer
    x = 538.59

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.